Count the number of occurrences of 1 in 0 to 0.1 billion-PHP source code

Count the numbers from 0 to 0.1 billion.

function count_n($limit, $n) {  if ($limit < $n) {    return 0;  }  if ($limit == $n) {    return 1;  }  $power = floor(log10($limit));  $unit = pow(10, $power);  $high = floor($limit / $unit);  $low = $limit % $unit;  return $high * $power * $unit / 10      + (($high > $n)? $unit: (($high == $n)? 1 + $low: 0))      + count_n($low, $n);}echo count_n(100000000, 1); // 80000001

2. [Code]Functions originally written in newLisp

(define (count-n limit n)  (if (< limit n) 0    (= limit n) 1    (letn (high (int ((string limit) 0))           low (int (1 (string limit)))           power (int (log limit 10)))      (+ (count-n low n)         (* high power (pow 10 (- power 1)))         (if (> high n) (pow 10 power)           (= high n) (+ 1 low)           0)))))(println (count-n 100000000 1))